Cellulose produced by filamentous fungi

ABSTRACT

The present invention relates to a method of producing cellulose comprising the steps of:  
     (i) culturing filamentous fungus having the ability to produce cellulose; and  
     (ii) recovering cellulose from a culture obtained by the step (i) and  
     cellulose produced by filamentous fungi.  
     The present invention provides technology to produce cellulose from filamentous fungi. Further, the present invention provides novel cellulose, which is produced by filamentous fungi and can be utilized as various industrial materials, additives, and the like.

FIELD OF THE INVENTION

[0001] The present invention relates to microbial production ofcellulose, in particular, to a method of producing cellulose usingcellulose-producing fungi belonging to psychrophilic filamentous fungiand cellulose obtained by this production method.

BACKGROUND OF THE INVENTION

[0002] Cellulose is a major constituent of the cell wall of plants. Mostcellulose for use as paper is derived from plants, such as woods.

[0003] In addition to plants, some bacteria, prokaryotic organisms,produce extracellular cellulose, called bacterial cellulose, in theculture medium during cultivation. Because of its superior property ofdispersing in water, the bacterial cellulose has been utilized as anadditive for food and cosmetics. Since it has physical propertiesdifferent from those of cellulose produced from a wood pulp and thelike, it has been applied as various industrial materials, for example,to an acoustic oscillation board in an audio speaker.

[0004] On the other hand, filamentous fungi, which are eukaryotes, areknown to produce extracellular polysaccharides. Among polysaccharidesproduced by such filamentous fungi, polysaccharides, which have beenreported so far to consist of glucose, similar to cellulose, areα-glucan including pullulan and elsinan, and β-glucan including β-(1→3)-glucan with branches or side chains of β-(1→3)·(1→6)-glucan andβ-(1→6)·β-(1→4) glucan.

[0005] It has not been reported that filamentous fungi produce cellulosewhich is β-(1→4)-glucan.

SUMMARY OF THE INVENTION

[0006] The object of this invention is to provide a method of producingcellulose using filamentous fungi and cellulose produced by thefilamentous fungi.

[0007] As a result of diligent research to solve the above problems, theinventors have completed the invention by finding that Microdochiumnivale belonging to psychrophilic filamentous fungus produces insolublepolysaccharide in a large quantity in the culture medium duringcultivation of the organism, and produced polysaccharide is cellulose.

[0008] The present invention encompasses the following inventions.

[0009] (1) A method of producing cellulose comprising the steps of:

[0010] (i) culturing filamentous fungus having the ability to producecellulose; and

[0011] (ii) recovering cellulose from a culture obtained by the step(i).

[0012] (2) The method of (1), wherein the filamentous fungus belongs tothe genus Microdochium.

[0013] (3) The method of (1), wherein the filamentous fungus isMicrodochium nivale (FERM BP-7298).

[0014] (4) Cellulose produced by filamentous fungus.

[0015] (5) The cellulose of (4), wherein the filamentous fungus belongsto the genus Microdochium.

[0016] (6) The cellulose of (4), wherein the filamentous fungus isMicrodochium nivale (FERM BP-7298).

[0017] (7) Cellulose which is obtained by the method of (1).

[0018] (8) Cellulose which has the physico-chemical properties of:

[0019] (a) being completely hydrolyzed when it is treated in 2Mtrifluoroacetic acid for 2 hours at 121° C.; and (b) showing no peak at2θ=5.0° to 45.0° when it is lyophilized (freeze-dried) and subjected toX-ray diffraction analysis.

[0020] This specification includes part or all of the contents asdisclosed in the specification and/or drawings of Japanese PatentApplication Nos.1999-281425 and 2000-275211, which is a prioritydocument of the present application.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 is a graph showing (A) Changes with time in the amount ofextracellular insoluble polysaccharide produced by Microdochium nivalewhile culturing the organisms at 4° C., and (B) The relationship betweenthe amount of extracellular insoluble polysaccharide produced fromMicrodochium nivale and the culture temperature. Symbols:  indicatesthe amount of insoluble polysaccharides and ▪0 indicates the amount ofMicrodochium nivale cells.

[0022]FIG. 2 shows the results of constituent sugar analysis by gaschromatography performed on insoluble polysaccharide produced byMicrodochium nivale.

[0023]FIG. 3 shows the results of FT-IR analysis on insolublepolysaccharide produced by Microdochium nivale.

[0024]FIG. 4 shows the analytical results of the linking pattern betweenglucose units in the insoluble polysaccharide produced by Microdochiumnivale.

[0025]FIG. 5 shows the results of gel filtration chromatographyperformed on the insoluble polysaccharide produced by Microdochiumnivale.

[0026]FIG. 6 shows X-ray diffraction of (A) insoluble polysaccharideproduced by Microdochium nivale, and (B) a filter paper (Whatman)(vegetable cellulose).

DESCRIPTION OF THE PREFERED EMBODIMENTS

[0027] The present invention relates to cellulose produced byfilamentous fungi. Filamentous fungi used herein may be any filamentousfungi having the ability to produce cellulose, without other limitation.Preferred examples of the filamentous fungi are, but are not limited to,those belonging to the genera Microdochium. A particularly preferredfilamentous fungus is a snow mold, Microdochium nivale, which wasdeposited with National Institute of Bioscience and Human Technology,Agency of Industrial Science and Technology (1-3, Higashi 1-chome,Tsukuba-shi, Ibaraki-ken 305-0046, Japan) on Sep. 2, 1999 (Accession No.FERM BP-7298)

[0028] The present invention also relates to a method of producingcellulose comprising the steps of (i) culturing filamentous fungushaving the ability to produce cellulose; and (ii) recovering cellulosefrom a culture obtained by step (i). The filamentous fungus used in thismethod is as described above. According to this method, cellulose of theinvention can be properly produced.

[0029] Media used for culturing the filamentous fungus may be any mediaknown to allow filamentous fungi to grow, without other limitation.Either liquid or solid media may be used. Preferably, a liquid medium isemployed. A particularly preferred medium used in the invention is aliquid potato dextrose medium.

[0030] Culturing may be performed by any method known to those skilledin the art, including shaking culture, stationary culture, and the like.A preferred culturing method is shaking culture. In liquid culture, theamount of cells added to a medium is not specifically limited because itcan be properly determined by those skilled in the art. The amount ofcells to be added per 200 ml of a medium is preferably 0.01 g to 0.15 g,more preferably 0.04 g to 0.08 g.

[0031] When the amount of cells is represented by weight in thisspecification, unless otherwise specified, the cell amount isrepresented by the wet weight (weight of cells in wet conditions) whichis obtained by centrifuging cultured cells to remove the supernatantfluid.

[0032] Further, in solid culture, the amount of cells added to a mediumis not specifically limited because it can be properly determined bythose skilled in the art.

[0033] Temperature for culturing is not specifically limited, because itcan be determined based on the results of examinations for efficiency ofcellulose production by filamentous fungi at various temperatures. WhenMicrodochium nivale (FERM BP-7298) is used as filamentous fungus,culture temperature may be determined according to graph B in FIG. 1.Temperature for culturing is not specifically limited as describedabove. However in a temperature range below 10° C., a preferredtemperature ranges from 2° C. to 8° C., more preferably 3° C. to 6° C.,and the most preferably at about 4° C. In a temperature range above 10°C., a preferred temperature ranges from 12° C. to 25° C., morepreferably 15° C. to 22° C., and the most preferably at about 20° C.

[0034] The culturing period is not specifically limited, because it canbe determined based on the results of examinations for efficiency ofcellulose production by filamentous fungi for various culturing periods.When Microdochium nivale (FERM BP-7298) is used as filamentous fungusand cultured at 4° C., a culturing period may be determined according tograph A in FIG. 1. As described above, the culturing period is notspecifically limited. A preferred culturing period is from 7 to 35 days,more preferably 10 to 20 days, and the most preferably about 14 days.

[0035] According to the preferred embodiment of this invention,cellulose can be efficiently produced by inoculating and shake-culturingMicrodochium nivale (FERM BP-7298) in a potato dextrose (2.4%) liquidmedium (pH 5.1) for 14 days at 4° C. For example, when 0.06 g ofMicrodochium nivale is inoculated in 200 ml of the said liquid mediumand cultured while turning the medium placed in a 500 ml flask at 200rpm, 4 g/l of cellulose can be produced.

[0036] Thus produced intracellular or extracellular cellulose can berecovered by known methods. When cellulose is produced intracellularly,cellulose can be recovered by known methods from a mixture obtained fromthe disrupted cells. When cellulose is produced extracellularly,cellulose can be recovered by known methods from portions other than thecells in the culture. For example, cellulose produced in a liquid mediumcan be recovered by centrifuging the liquid medium to collect thefraction containing insoluble polysaccharide.

[0037] The recovered cellulose can be washed with distilled water andthe like. Moreover, the obtained cellulose can be subjected to variousprocessings or treatments according to its applications. Suchprocessings or treatments may be properly performed by those skilled inthe art.

[0038] It can be confirmed that the recovered insoluble polysaccharideis cellulose, by chemical analysis or instrumental analysis known tothose skilled in the art. For example, the insoluble polysaccharide canbe confirmed to consist of D-glucose by constituent sugar analysis, suchas alditol acetate method. Further, each glucose unit can be confirmedto be type β (that is, each three-dimensional configuration betweenglucose units is type β) according to an absorbance at 890 cm⁻¹ byinfrared rays absorption analysis (IR). Furthermore, in constituentsugar analysis using sodium borodeuteride (NaBD₄) as a reducing agentafter complete methylation, each linking pattern between glucose unitsis confirmed to be (1→4) linking. This can also be confirmed by othermethods, such as Smith degradation. Chemical analysis and instrumentalanalysis as described above are routinely employed in the art, thus theycan be appropriately performed by those skilled in the art.

[0039] The molecular weight of cellulose according to the invention canbe measured using methods known to those skilled in the art, includinggel chromatography using gel filtration, gel permeation chromatography(GPC), and the like. Gel used for gel filtration is not specificallylimited, because those skilled in the art can select a proper gel. Apreferred gel is TSKgel HW-65F. Thus determined molecular weight ofcellulose according to the invention is not specifically limited. Apreferred molecular weight of the cellulose ranges from 350,000 to800,000, more preferably 500,000 to 700,000, and the most preferablyabout 600,000. The resultant average molecular weight (Mw) is preferably550,000 to 600,000, more preferably about 5,750,000.

[0040] The crystal structure of the cellulose of the invention can bedetermined by X-ray diffraction. Process for X-ray diffraction is notspecifically limited. For example, insoluble polysaccharide (celluloseof the invention) obtained as described above is put into a plasticcontainer with a flat and smooth surfaced bottom, and freeze-dried toprepare a film with a smooth surface (1 mm of thickness, 14 mm×14 mm).X-ray diffraction analysis can be performed by irradiating X-rays overthis smooth surface. When cellulose is analyzed by this concretetechnique, the cellulose of the invention shows no peak at 2θ=5.020 to45.0°. That is, the cellulose of the invention has no definite crystalstructure.

[0041] In the above constituent sugar analysis, when treated with 2Mtrifluoroacetic acid for 2 hours at 121° C., the cellulose of theinvention is completely hydrolyzed to glucose, but known vegetablecelluloses resist against such hydrolysis and are not completelyhydrolyzed. Further, in X-ray diffraction as described above, thecellulose of the invention shows no peak at 2θ=5.0° to 45.0°, but theknown vegetable celluloses show peaks at 2θ=14.6°, 16.5° and 22.7°. Thissuggests that the cellulose of the invention has no definite crystalstructure while the known vegetable celluloses have a crystal structureidentical to understandings obtained so far. Therefore, the cellulose ofthe invention is totally different from known celluloses.

[0042] Accordingly, the present invention relates to cellulose havingthe physico-chemical properties of:

[0043] (a) being completely hydrolyzed when it is treated in 2Mtriflubroacetic acid for 2 hours at 121° C.; and

[0044] (b) showing no peak at 2θ=5.0° to 45.0° when it is lyophilized(freeze-dried) and subjected to X-ray diffraction analysis.

[0045] The molecular weight of the cellulose, which is not specificallylimited, is preferably 350,000 to 800,000, more preferably 500,000 to700,000, and the most preferably about 600,000. The molecular weight isdetermined by dissolving 1 mg of insoluble polysaccharide obtained asdescribed above in 0.5 ml of cadoxen (tris(ethylendiamine) cadmiumhydroxide), subjected to gel chromatography (TSKgel HW-65F, 15 cm×0.5cm), fractionated every 2 minutes (flow rate: 0.3 ml/minute), thenanalyzing the sugar content of each fraction by the phenol-sulfuric acidmethod. The resultant average molecular weight (Mw) is preferably550,000 to 600,000, more preferably about 5,750,000.

[0046] Industrial Applicability

[0047] The present invention provides technology to produce cellulosefrom filamentous fungi. Further, the present invention provides novelcellulose, which is produced by filamentous fungi and can be utilized asvarious industrial materials, additives, and the like.

EXAMPLES

[0048] The present invention is further described in the followingexamples. These examples are provided for illustrative purposes only,and are not intended to limit the scope of the invention.

Example 1

[0049] Culture of Microdochium nivale and Recovery of InsolublePolysaccharide

[0050] 0.06 g of Microdochium nivale (FERM BP-7298) was inoculated in200 ml of a potato dextrose (2.4%) liquid medium (pH 5.1) (manufacturedby Difco) and cultured while turning the medium placed in a 500 ml flaskat 200 rpm. The culture medium was centrifuged (15,000×g, 20 minutes) tocollect jelly-like substances in the upper layer of the precipitatedcells. The collected substances were washed with distilled water toobtain insoluble polysaccharide.

[0051] The productivity of the insoluble polysaccharide was examined inthe above culturing process by varying the culture temperature in therange of 4° C. to 20° C.

[0052] In FIG. 1B showing the results of this examination, each valuerepresents a dry weight per litter of the culture medium at a point whenthe maximum amount of extracellular insoluble polysaccharide wasproduced at each temperature (4° C. : on day 14, 10° C.: on day 14, 15°C.: on day 4, 20° C.: on day 6). The symbol, “” indicates the amount ofinsoluble polysaccharide and “▪” indicates the amount of filamentousfungus. The highest productivity was seen in the culturing at 4° C.according to FIG. 1B.

[0053] Next, changes with time in the amount of insoluble polysaccharideproduced in case of culturing Microdochium nivale at 4° C. wereexamined. FIG. 1A shows the results of this examination. The symbol “”indicates the amount of insoluble polysaccharide and “▪” indicates theamount of filamentous fungus in FIG. 1A. Insoluble polysaccharideproduced in the culture fluid continued to increase until day 14 then itstarted to decrease according to FIG. 1A.

[0054] Based on these results, 0.06 g of Microdochium nivale wascultured for 14 days at 4° C. Thus, insoluble polysaccharide, 4 g perliter of the culture medium, was obtained.

Example 2

[0055] Identification of Insoluble Polysaccharide Produced byMicrodochium nivale.

[0056] (1) Constituent Sugar Analysis

[0057] 0.5 ml of 2M trifluoroacetic acid was added to 1 mg of insolublepolysaccharide obtained in Example 1, then the mixture was hydrolyzedfor 3 hours at 121° C. Trifluoroacetic acid was removed from the mixtureusing nitrogen gas. The resulting monosaccharide was reduced with sodiumborohydride. The hydroxyl groups of the reduced monosaccharide wereacethylated by Merkle and Poppe's method (Merkle and Poppe, MethodsEnzymol. 230, 1-15, 1994). Analysis with gas chromatography (column;Spelco SP-2330: internal diameter 0.25 mm×length 15 m, temperaturecondition; kept at 170° C. for 4 minutes: elevated from 170° C. to 240°C. at a rate of 8° C./minute: kept at 240° C. for 8 minutes) resulted ina peak only for acethylated glucose. Therefore the insolublepolysaccharide was confirmed to be polyglucan (FIG. 2).

[0058] (2) Determination of Three-Dimentional Configuration for Carbonat Position 1 in Glucose

[0059] The insoluble polysaccharide obtained in Example 1 wasfreeze-dried, and then ground down together with potassium bromide andshaped into tablets. Subsequently the three-dimentional configuration ofcarbon at position 1 in the glucose was examined by Fourier transforminfrared rays absorption analysis (FT-IR). As a result, a peak wasdetected at 890 cm⁻¹, suggesting that this was type β (FIG. 3).

[0060] (3) Determination of the Linking Pattern Between Glucose Units

[0061] To examine the linking position of glucose in the insolublepolysaccharide obtained in Example 1, hydroxyl groups existing in theinsoluble polysaccharide were completely methylated, and subjected toconstituent sugar analysis as described in (1) except that sodiumborodeuteride (NaBD₄) was used for reduction.

[0062] The complete methylation was performed as follows. First, 10 mlof dimethyl sulfoxide (DMSO) was added to 80 mg of insolublepolysaccharide, then the mixture was stirred in a flask with argon gassealed therein for 2 hours, followed by ultrasonication for 2 hours. Theinsoluble polysaccharide dissolved partially. To completely dissolve theinsoluble polysaccharide, an additional 15 ml of DMSO and 9 ml of sodiumdimsyl (The sodium dimsyl had been prepared by adding 10 ml of DMSO to0.5 g of oleaginous sodium hydride in a flask containing argon gassealed therein) were added to the mixture, then stirred for 2 minutesfollowed by ultrasonication for 2 minutes. Then 1 ml of methyl iodidewas added to the mixture in ice and dialyzed against distilled water.

[0063] Thus obtained products were analyzed with a gas chromatographymass spectrometer (GC/MS) (Column: SpelcoSP-2330, Internal diameter 0.25mm×Length 15 m, Temperature condition: maintained for 4 minutes at 19020C.; elevated from 190 to 240° C. at a rate of 4° C./minute; maintainedfor 8 minutes at 240° C.). A control was prepared by similarly treatingthe standard sample of cellulose, whose 30% of hydroxyl groups hadalready been methylated. FIG. 4 shows the results. In FIG. 4, “A”indicates the gas chromatogram of the insoluble polysaccharide; “C”indicates the mass spectrum of substances eluted at about 12 minutes ofthe gas chromatogram of “A”; “B” indicates the gas chromatogram of 30%methylated cellulose; and D indicates the mass spectrum of substanceseluted at about 12 minutes in the gas chromatogram of “C.” As shown inFIG. 4, for the insoluble polysaccharide, only glucose whose carbons atpositions 2, 3 and 6 had been methylated was detected.

[0064] (4) Conclusion

[0065] The results obtained in (1) to (3) above suggest that theinsoluble polysaccharide consisted only of cellulose, which isβ-(1→4)-glucan.

Example 3

[0066] Molecular Size of Cellulose

[0067] 1 mg of insoluble polysaccharide obtained in Example 1 wasdissolved in 0.5 ml of cadoxen (tris(ethylendiamine) cadmium hydroxide),subjected to gel chromatography (TSKgel HW-65F, 15 cm×0.5 cm), and thenfractionated every 2 minutes (flow rate: 0.3 ml/minute). Analysis of thesugar content of each fraction by the phenol sulfuric acid methodresulted in a single peak, as shown in FIG. 5. Molecular weight wasmeasured using dextran (molecular weight: 12,000, 50,000 and 150,000) asa standard sample. The majority of the insoluble polysaccharide hadmolecular weight of 600,000. The average molecular weight (Mw: weightaverage molecular weight) was 5,750,000.

Example 4

[0068] Crystal Structure Analysis

[0069] The insoluble polysaccharide obtained in Example 1 was put into aplastic container with a flat and smooth bottom and freeze-dried toprepare a film with a smooth surface (1 mm of thickness, 7 mm×7 mm).Then X-ray diffraction analysis was performed by irradiating X-ray overthe smooth surface. This analysis resulted in no definite peak. On theother hand, X-ray diffraction analysis made for a filter paper (Whatman)as a control resulted in peaks at 2θ=14.6°, 16.5°, and 22.7°, which isspecifically observed for the three-dimensional structure of vegetablecelluloses. Therefore, it was shown that unlike known vegetablecelluloses, the insoluble polysaccharide has no definite crystalstructure.

[0070] All publications, patents and patent applications cited hereinare incorporated herein by reference in their entirety.

[0071] Translation of an Extract of the Rule of IndependentAdministrative Institutes National Agricultural Research Organization(1999 Japanese Law No. 192)

[0072] Chapter I: General Rule

[0073] (Object)

[0074] Art. 1: The object of this law is to legislate the name, thepurpose, the scope of tasks and so on of the Independent AdministrativeInstitutes National Agricultural Research Organization.

[0075] (Name)

[0076] Art. 2: The name of the Independent Administrative Instituteestablished according to this law and the General Rule of IndependentAdministrative Institutes (1999 Japanese Law No. 103) shall be NationalAgricultural Research Organization.

[0077] (Purpose)

[0078] Art. 3: The purpose of the National Agricultural ResearchOrganization (hereinafter called as Research Organization) shall be tocontribute to the progress of agricultural technology.

[0079] (Office)

[0080] Art. 5: The head office of the Research Organization shall belocated in Ibaraki, Japan.

[0081] Chapter III: Tasks etc.

[0082] (Scope of task)

[0083] Art. 10: In order to attain the purpose according to Art. 3, theResearch Organization shall take charge of the following tasks;

[0084] (1) General examination, research and search regardingagricultural technology.

[0085] Supplementary Provision

[0086] (Succession of Rights and Duties)

[0087] Art. 5: The Research Organization shall succeed all the rightsand duties relating to the tasks of Art. 10, which are owned by theState at the establishment of the Research Organization and named by agovernment ordinance.

[0088] Translation of an Extract of the Government Ordinance forArrangement of the Relating Government Ordinance and TransitionalMeasures at the Enforcement of the General Rule of the IndependentAdministrative Institutes etc. (1999) Japanese Government Ordinance No.326)

[0089] (Rights and Duties Succeeded by Independent AdministrativeInstitutes)

[0090] Art. 35: The rights and duties to be named by the governmentordinance that is legislated by the provision described in column 1 ofTable 1 shall be as follows;

[0091] (1) The rights and duties named by the Minister described incolumn 3 relating to the lands, buildings, constructs, shipping andaircrafts which are belong to the department or organization describedin column 2 of Table 1.

[0092] (2) The rights and duties relating to the articles used in thedepartment or organization described in column 2 of Table 1 at theestablishment of the Independent Administrative Institutes described incolumn 4 of Table 1.

[0093] (3) The rights and duties other than the above (1) and (2) whichare owned by the State relating to the task of the IndependentAdministrative Institutes described in column 4 and named by theMinister described in column 3 of Table 1 TABLE 1 1 Provision Rule ofthe Independent Administiative Institutes National Agricultural ResearchOrganization Supplementary Provision, Art. 5 2 Department/ NationalAgriculture Research Center; Organization National Research Institute ofVegetable, ornamental Plants and Tea; National Institute of Fruit TreeScience; National Institute of Animal Industry; National GrasslandResearch Institutes National Institute of Animal Health and NationalAgriculture Experiment Station Belonging to Ministry of Agriculture,Forestry and Fishery 3 Minister Minister of Agriculture, Forestry andFishery 4 Independent National Agricultural Research OrganizationAdministrative Institutes

What is claimed is:
 1. A method of producing cellulose comprising thesteps of: (i) culturing filamentous fungus having the ability to producecellulose; and (ii) recovering cellulose from a culture obtained by thestep (i)
 2. The method according to claim 1 wherein the filamentousfungus belongs to the genus Microdochium.
 3. The method according toclaim 1 wherein the filamentous fungus is Microdochium nivale (FERMBP-7298).
 4. Cellulose produced by filamentous fungus.
 5. The celluloseaccording to claim 4 wherein the filamentous fungus belongs to the genusMicrodochium.
 6. The cellulose according to claim 4 wherein thefilamentous fungus is Microdochium nivale (FERM BP-7298).
 7. Cellulosewhich is obtained by the method according to claim
 1. 8. Cellulose whichhas the physico-chemical properties of: (a) being completely hydrolyzedwhen it is treated in 2M trifluoroacetic acid for 2 hours at 121° C.;and (b) showing no peak at 2θ=5.0° to 45.0° when it is lyophilized andsubjected to X-ray diffraction analysis.
 9. An isolated polysaccharidemade by a process comprising the following steps (a) culturing orisolating a sample of filamentous fungus belonging to a genusMicrodochium; (b) recovering from the filamentous fungus of step (a) asample consisting essentially of a cellulose, wherein the celluloseconsists essentially of a beta-(1→4)-glucan polysaccharide.
 10. Anisolated beta-(1→4)-glucan polysaccharide, wherein the polysaccharide isisolated from a culture or isolate of a filamentous fungus belonging toa genus Microdochium.
 11. An isolated cellulose produced by a processcomprising the steps of: (a) culturing a filamentous fungus in a culturemedia, wherein the filamentous fungus is a genus Microdochium funguscomprising an ability to produce a cellulose in a culture media; (b)centrifuging the culture media; and (c) recovering a jelly-likesubstance in an upper layer of the centrifuged culture media.
 12. Anisolated cellulose, wherein the cellulose is isolated from a samplecomprising a secretion of a filamentous fungus belonging to the genusMicrodochium.
 13. The isolated polysaccharide of claim 9, wherein thefilamentous fungus is a Microdochium nivale.
 14. The isolatedpolysaccharide of claim 13, wherein filamentous fungus is a Microdochiumnivale deposited as FERM Accession No. BP-7298.
 15. The isolatedpolysaccharide of claim 9, wherein the recovering of step (b) furthercomprises harvesting an insoluble polysaccharide from a culture or anisolate of a Microdochium.
 16. The isolated polysaccharide of claim 9,wherein the culturing of step (a) comprises a culturing in a liquid or asolid media.
 17. The isolated polysaccharide of claim 16, wherein theliquid media comprises a dextrose medium.
 18. The isolatedpolysaccharide of claim 17, wherein the dextrose medium comprises apotato dextrose medium.
 19. The isolated polysaccharide of claim 9,wherein the culturing of step (a) comprises a shaking culture or astationary culture.
 20. The isolated polysaccharide of claim 9, whereinthe recovering of step (b) further comprises centrifuging a culturemedia and harvesting an insoluble polysaccharide.
 21. The isolatedpolysaccharide of claim 20, further comprising washing the insolublepolysaccharide with distilled water.
 22. The isolated polysaccharide ofclaim 9, wherein the cellulose has a molecular weight of between about350,000 MW and about 800,000 MW.
 23. The isolated polysaccharide ofclaim 22, wherein the cellulose has a molecular weight of between about500,000 MW and about 700,000 MW.
 24. The isolated polysaccharide ofclaim 23, wherein the cellulose has a molecular weight of between about600,000 MW.
 25. The isolated polysaccharide of claim 9, wherein inlyophilized form the X-ray diffraction pattern of the cellulose has nopeak at 2θ=5.0° to 45.0°.